1. Field of the Invention
The present invention relates integrated circuits and more particularly, to a circuit for generating to a power-on reset (POR) signal after a sudden variation in supply voltage.
2. Discussion of Related Art
In integrated devices, and particularly in nonvolatile memories, POR signal generating circuits are frequently used to initialize the various parts of the device and ensure a definite start state. Known circuits only function correctly if activated by rising transitions in supply voltage, which is normally an acceptable condition in devices with adequate protection against a sudden fall in supply. However, in some devices featuring timed circuits or comprising flip-flops or latches, the above stability condition is impaired by any sudden noise on the power supply line resulting in a marked, rapid fall (bump) in supply. This fall in supply in supply may result in errors, which are only recoverable by turning off and re-initializing the device and may be accompanied by a loss of data.